1. Field of the Invention
The present invention relates to a semiconductor device and a display device and, more particularly, to a semiconductor device configured to output image signals and to a display device.
2. Description of Related Art
Traditionally, electronic equipment such as mobile phones have been widely used and in the mobile phone, various types of processing including image processing for displaying images on a display unit are performed. Such image processing and other types of processing are achieved using semiconductor devices.
When such image processing is performed, the semiconductor device collectively outputs a plurality of image signals from a control portion to a display unit (for example, a liquid crystal display, which is hereinafter referred to as an LCD) for each picture element (i.e., one pixel) of a color image. For example, if each of the three RGB colors is represented by an 8-bit signal, a 24-bit image signal is necessary to display a single pixel and therefore 24-bit image signals are outputted in parallel on a pixel-by-pixel basis. If each of the three RGB colors is represented by a 6-bit signal, an 18-bit image signal is necessary to display a single pixel and therefore 18-bit image signals are outputted in parallel on a pixel-by-pixel basis. If each of the RB colors is represented by a 5-bit signal and the G color is represented by a 6-bit signal, a 16-bit image signal is necessary to display a single pixel and therefore 16-bit image signals are outputted in parallel on a pixel-by-pixel basis.
Accordingly, the semiconductor device outputs a plurality of image signals both simultaneously and in parallel.
However, outputting a plurality of image signals both simultaneously and in parallel causes a large amount of power to be consumed partially and instantaneously within the semiconductor device. If a large amount of power is consumed partially and instantaneously within the semiconductor device, a short supply of power may occur in other areas of circuitry within the semiconductor device. If a necessary amount of power is not supplied to any part of the semiconductor device, the circuitry within the semiconductor device may malfunction.
As a method for reducing such maximum instantaneous power consumption in a display device, there is proposed a method for feeding data signals to different groups of signal electrodes at shifted timings in Japanese Patent Laid-Open No. 2002-341820. In the configuration of the proposed method, data load instructions are generated so that a plurality of signal-side drive means are driven independent of each other. However, no specific means is shown against the above-described problem that a large amount of power is consumed partially and instantaneously within the semiconductor device or the like when a plurality of image signals are transmitted or received both simultaneously and in parallel.
Another possible solution is to simply divide a plurality of image signals and output them in units of the image signals thus divided. Divisional output is not preferable, however, in terms of image processing speed and becomes even more undesirable as the screen size of a display device increases.
The present invention has been accomplished in view of the above-described problems and an object of the present invention is to provide a semiconductor device capable of suppressing instantaneous current consumption (peak current) in outputting a plurality of image signals.